It's a moment many of us will have had and one which strikes a note of fear into a crescendo of panic in any racing scenario. It could well be argued that it is a natural selection of a physiological sense playing out in front of our eyes. Sometimes manageable but often only by an unwelcome lowering of exercise intensity, muscle cramps are the graveyard of any event!
Exercise Associated Muscle Cramp (EAMC) is a subject which is often debated and tested yet never given a conclusive, factual, evidence-based answer. What is consistent across the varying theories is the outcome, which is an involuntary contraction or over-shortening of the muscles.
In unearthing the various theories of why EAMC occurs you need only go back over the factors associated with times when you have cramped. Let's face it, they generally aren't jumping out of the tarmac on a nice, temperate day on a club-spin to intersect your hamstring and put you out the back.
Salt and vinegar on your cramps Sir? Imbalance of electrolytic fluids
Hot days, and more specifically sharp changes in temperature and unacclimated conditions force the body to excrete more sweat than normal. We lose body fluid as our cooling system tries furiously to regulate heart rate, blood pressure and our core temperature so that we don't cook our vital organs.
The extracellular fluid which surrounds our muscles is a salty-mixture of electrolytes and water, of which sodium is the greatest part. When we sweat to cool our muscles and regulate our core temperature we lose this sodium.
Replacing water is essential but replacing it without the sodium is where problems occur. Case studies suggest that it's this electrolyte or fluid imbalance which causes misfiring of nerve impulses and in turn cramps. The situation is further exacerbated when we take into account how vital sodium is in our bodies and how the body prioritises it's use after ingestion. Nutrient absorption in the gut, supporting cognitive function and nerve impulse transmissions are all also reliant on sodium so the processing it of it isn't as simple as might seem. It can't be assumed that a normal diet is getting enough sodium in to support even a moderate training week.
The solution, quite literally, is what we drink in both training and racing. We must, as best as possible, match the fluid and electrolytes lost through sweating, so we need to put back the sodium lost in our sweat. Preference should always be given to using electrolyte tablets in water over plain water in your bottles, and even a little of those in carbohydrate drink filled bottles.
Everyone has a different sodium concentration in their sweat but it is consistent day to day, so finding your rate will give an idea of how much you need to replace. Striking the balance might be trial and error but you can look for cues that you lose more sodium in your sweat than normal by the amount of salt accumulated on your bib shorts or by taking a one-time lab test.
Ironically another suggested cure for leg cramp is vinegar, specifically apple cider vinegar. With a high potassium and calcium concentration, it is believed to create a good electrolyte balance prior to intense exercise.
"Doctor it hurts when i touch mY toes!"..."Don't touch your toes then Sir"
There is strong scientific evidence, and also very much common sense to support the idea that EAMC are localised effects from neuromuscular fatigue. Lab-based tests make a strong argument that fatigue occurring between the muscle spindles which excite contraction and the opposing relaxation or inhibitory signals sent from the Golgi tendon organs is what causes a cross-wiring and EAMC occur. It certainly feels like the on-switch is stuck ‘on’ when cramp occurs! Common sense also points to this. Whilst it may take time to change the bodies electrolyte balance, cramp can occur in under a minute if a specific load is targeted on a muscle.
As much as it may feel like we are pushing huge force through the pedals in a single pedal motion, in terms of pure Newtons we aren't really. What we are doing is repeating the action over time. If this action is in a single locked position we are more likely to induce localised fatigue than if we moved to another albeit subtly different position, for instance moving from seated to standing on the pedals. It's no coincidence that you are more likely to experience a hamstring cramp in a fast, flat racing circuit before issues on your quadriceps.
The good news in relation to this idea is that while fatigue might not be totally reversible it can be delayed with training stimulus and subsequent adaptions. In short, more specific training to when EAMC occurs. A common mistake is the misplacement of efforts in training rides. Masking a problem with individual personal best power figures ignores the definition of fitness: suitability for purpose.
Poorly fitted positions can add additional stress to muscles which aren't optimal in the pedalling stroke. Asking smaller less powerful muscles to contribute more will cause early fatigue and potentially EAMC. A seasonal bike-fit is something we should all consider, so this isn't a service you may not need.
Postural issues or biomechanical deficiencies can also be the cause of the early onset of fatigue, it's worth talking to a sports therapist or getting a biomechanical assessment if you are experiencing chronic EAMC in one area. It may be as simple as addressing that through specific strength and conditioning exercises.
A lack of protein or amino acids in your diet could also add to both early fatigue and or imbalance of the intracellular fluids. Amino acids are present in skeletal muscle tissue and prevent the amount of damage afflicted upon the muscles during intense physical activity. Consider supplementing protein and amino acids like taurine but also just increase your intake of good natural sources like Salmon, dark turkey meat and shellfish.
There may not always be an immediate answer to the problem of cramp but with some of the preventative measures I've mentioned hopefully, there is a little light at the end of the tunnel.
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